Controller for vehicle

Abstract

A controller for a vehicle makes it possible to prevent window glass from fogging and also to reduce fuel consumption in conducting control to temporarily stop an engine when a vehicle stops. The controller for a vehicle includes a vehicle condition detector which detects a condition under which a vehicle is being placed, a fogging determination humidity estimator which estimates a fogging determination humidity, which is a humidity not causing window glass of the vehicle to fog up under the condition detected by the vehicle condition detector, a humidity detector which detects the humidity in the vehicle, and an engine stop duration determiner which determines a longer engine stop duration as the humidity difference increases between the humidity detected by the humidity detector immediately before an engine is stopped and the fogging determination humidity. An engine control unit restarts the engine and also starts up a refrigeration cycle unit and a blower fan when an engine stop duration has elapsed following an engine stop.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to a controller for a vehicle which stops an engine mounted in a vehicle when a stop condition holds while the engine is in operation, and restarts the engine when a start condition holds while the engine is at rest.[0003]2. Description of the Related Art[0004]Hitherto, there has been known a controller for a vehicle adapted to temporarily stop an engine while a vehicle is at rest thereby to restrain fuel consumption from idling while the vehicle is at rest (refer to, for example, Japanese Patent Application Laid-Open No. H4-358729).[0005]In a conventional controller for a vehicle, an engine is stopped when the vehicle speed reaches zero and the vehicle stops and the clutch switch turns off (i.e., when a stop condition holds), and the engine is restarted when a predetermined time has elapsed following the engine stop (i.e., when a start condition holds).[0006]Further, in the conventional co...

AI Technical Summary

Benefits of technology

The present invention relates to a controller for a vehicle that reduces fuel consumption while resting the engine while still preventing fogging of the window glass. The controller includes an engine controller that stops the engine when a predetermined stop condition is met and restarts the engine when a predetermined engine stop duration has elapsed. The controller also includes a vehicle condition detector that detects conditions under which the vehicle is placed, such as the temperature outside the vehicle and the humidity in the vehicle. By estimating the fogging determination humidity and using the engine stop duration determined based on the humidity difference, the controller can restrain fuel consumption while still preventing fogging of the window glass. Additionally, the controller can use the blower fan to circulate air in the vehicle and dehumidify the interior of the vehicle, further reducing fuel consumption.

Problems solved by technology

Here, if the time from the stop to the restart of the engine is fixed, as with the conventional controller for a vehicle, there are cases where the window glass of the vehicle undesirably fogs up due to a rise in humidity in the vehicle by the time the engine is restarted, depending on the outside air or the condition in the vehicle when the vehicle stops and the engine stops after the interior of the vehicle has been naturally ventilated by the travel of the vehicle or if a dehumidifier has been operated from the driving force of the engine until the engine stops and the operation of the dehumidifier stops as the engine stops.

The fogging up of the window glass inconveniently forces the driver to defog the window glass when he / she restarts the vehicle.

On the other hand, if the time from the stop to the restart of the engine is set to be shorter so as to prevent the window glass from fogging up, then the effect for restraining fuel consumption by stopping the engine while the vehicle is at rest would be inconveniently inadequate.

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